1. Field of the Invention
The present invention relates to farm and to other machinery having a device or devices driven by two or more hydraulic motors and wherein it is desirable to vary stepwise and automatically the power fed to each motor.
2. The Prior Art
In prior art devices known to the applicant such as manure spreaders for farm use, a pair of horizontally-extending beater axles are arranged in the rear of a hopper bed or trailer for shearing and flinging outwardly onto a field a load of solid material such as animal waste. Hydraulic motors driving the axles in the prior art were connected in series, with power controlled by varying the pressure and flow volume of hydraulic fluid fed thereto. Such devices had great difficulty in beginning to rotate under load, especially when the material was tightly compacted against the axles, or when the axles were retained by frozen chunks. In many cases the conventional hydraulic system would be unable to start the beaters rotating until material was cleared from the beaters by hand. In most cases, it was necessary in loading the hopper bed to keep material carefully away from the flinging bars.